A codebook provides information on the structure, contents, and layout of a data file. Look at the codebook of a study before downloading the data files.
While codebooks vary widely in quality and amount of information given, a typical codebook includes:
- Column locations and widths for each variable
- Definitions of different record types
- Response codes for each variable
- Codes used to indicate nonresponse and missing data
- Exact questions and skip patterns used in a survey
- Other indications of the content and characteristics of each variable
Additionally, codebooks may also contain:
- Frequencies of response
- Survey objectives
- Concept definitions
- A description of the survey design and methodology
- A copy of the survey questionnaire (if applicable)
- Information on data collection, data processing, and data quality
See a sample code book.